This would not be site wide. It would only be blocking your IP address. You would want to check if you have an RSS feed readers from your computer pointed to your community, anything like that which may be creating errors or lots of requests.
If this does not meet your usage, we would need to know what you're doing. Are you posting something specific which always gets blocked and then you can't do anything else? Are you trying to run an upgrade, third party install, etc... and it's failing? As this is happening right now specific to you, we need more information about what is happening.